LAWRENCE — Behind the door with the four-digit password and down the long hallway, Bill Self spins around in a leather chair to grab something out of his locker. This is in the coaches’ lounge, where he’s watching one of those sports blooper reels on TV, laughing at the football player who head-butts the cement wall. But now he wants to make a point. Hold on, he says.

The Kansas basketball coach turns serious. He’s looking for a play card. OK, here.

“Look at this,” he says, holding up a white laminated card with names like two-spin on them. “These are all our plays. One, two, three, four, five…”

He gets to 12. Twelve plays to run against man-to-man defense. Next column over are five plays for zone defense. That’s it. That’s the list. Self thought they’d have at least a few more by now. He wants to double those numbers by the start of conference play. Last season, when the Jayhawks reached the NCAA title game, they had around 40 plays for man defense and 12 for zone by February. He wants to move faster.

This, as much as anything else, is a good illustration of Self’s challenge as the coach of a roster with a rare and extreme split: 86 percent of KU’s minutes and 90 percent of the points are going to freshmen or seniors. There is no middle ground, and so far the freshmen are holding the seniors back more than the seniors are pulling the freshmen along.

“Nope, never had it before,” Self says. “I’ve had all older guys, and I’ve had all young guys. But never like this.”

This is the No. 9 Jayhawks’ biggest challenge. How well they navigate it will go a long way toward deciding whether they become a great team, or merely a good one.

One of the nation’s best coaches goes to work.

Bill Self loves this. He lives for this. Semester break, there are no limits on practice time and fewer games to break up the teaching moments. The only thing he’d change about this moment is the venue, because when you yell in an empty Allen Fieldhouse, your voice tends to echo and drown in all that space. Next door, in the smaller practice gym, a coach can scream with clarity.

But that’s OK. Has to be OK. Because freshman Anrio Adams just failed to “pinch” senior Elijah Johnson on a free throw attempt. Echoes be damned.

“I’m going to take you out immediately,” Self yells.

A minute later, and Adams must be listening because he just pinched Johnson hard. Of course, this just gives Self another teaching moment. This time for Johnson.

“You going to let him pinch you like that?” the coach asks.

The differences are subtle, but important. When the freshman messes up, the voice rises, the face reddens, sometimes practice stops. When the senior messes up, he’s more likely to hear a challenge. The older guys say Self makes the same points to everyone, he just makes them louder to the freshmen.

Self says he coaches this team the same as any other, but that’s true only because he coaches every player on every team differently. He looked at this season’s roster — his four seniors have now played 351 games; his top four freshmen 36 — and knew that choppy waters lay ahead.

Johnson doesn’t need much coaching. He can finish Self’s sentences. Travis Releford has been in the program five years — the freshmen were in seventh grade when Releford graduated high school — and will turn 23 later this season. Withey is one year younger than Blake Griffin, the former Oklahoma star now in his third NBA season.

The freshmen are, well, freshmen. Ben McLemore and Jamari Traylor spent last season on campus. They even practiced with the Jayhawks during the second semester, but only on the scout team. Self says they’re no further along in knowing the system than Perry Ellis — who was winning his fourth state high school title at Wichita Heights last spring.

Johnson is the senior point guard, and McLemore the projected freshman lottery pick. Self wants some of Johnson’s 108 games of experience to help McLemore’s nine. So far it’s been too much of the opposite. A lot of coaches would trade problems with Self, but this is what’s keeping the Jayhawks from being what they could be.

“We’ve gone so slow we’ve bored the older guys,” Self says. “I don’t talk to them about it, but I think it’s frustrating for them. If the younger guys could focus and be sponges more, we could go a little faster. But I don’t think they look at it like that, like, ‘We’re boring those other guys.’ I don’t think they think about it like that.”

This is partly because Self is coaching what he calls “the nicest guys ever.” He does not say this as a compliment. Self likes tough. He likes mean. Sherron Collins and Thomas Robinson are two of Self’s favorite players, and neither won any sportsmanship awards.

So Self tries to find places where the seniors can help the freshmen, or where the freshmen can be scared into helping themselves. When a friend and former NBA executive shows up at practice, Self winks at the man while yelling a fib to the team — the old executive said the Jayhawks don’t guard anyone.

When Johnson turns the ball over, Self points out the mistake and moves on. When McLemore does the same thing, Self stops practice to drive home the point. When Withey misses a rebound, Self challenges his toughness and moves on. When Ellis does the same thing, Self stops practice.

“That’s not going to fly here,” he says.

This is every coach’s balance, of course, but not to Self’s extreme. Usually there are sophomores and juniors to lean on, too. Usually Kansas doesn’t have a freshman like McLemore so talented he leads the team in points and shots. So Self mixes in encouragement (“we are getting better, I see that”) with bluntness (“you let everyone down when you do that”).

Already, the Jayhawks are behind where Self wants them. By a week or so. They’re behind where they were last year at this time, and behind where he thought they’d be at this time.

But there are signs. Good signs. Signs that old is mixing with new. Signs that old is pulling along new, veterans helping neophytes. On this day, the Jayhawks are running through some offensive sets. Johnson is the point guard, like usual. McLemore is the second or third option, but Johnson ends up taking the shot. He misses. An empty possession.

“Ben, you gotta work harder to get open there,” Self says.

McLemore nods his head.

“He was open, coach,” Johnson interjects. “I just missed him.”

“OK,” Self says, and you can see the beginning of a smile. “Let’s run it again.”

Back in the coach’s locker room there is an ease about Self, even by his own aw shucks standards. Self is easy. Telling old stories. Laughing at the bloopers. Every once in a while, he’ll veer off onto a game he caught the other night on television or that place on 23rd Street he used to go for wings.

He says he wants the freshmen to work harder — “I don’t think their try level is quite as high as I’d like,” is how he puts it — but that sense of panic from last year is gone now. Just as long as everything is in place by Big 12 Conference play, which means Jan. 9.

A year ago, he wasn’t like this. Not at all. A year ago, his team kept him up at night. He thought they were too wild, didn’t play enough defense, and didn’t trust themselves enough. He told friends he didn’t know whether his team would be any good. Wasn’t just coach-speak. People would tell him the team would end up winning a lot of games, and he’d raise his shoulders and shake his head, like, we’ll see.

On this day, he asks a familiar face for an assessment of his team. Really, really good, he hears. Self nods his head. Throws that play card back in his locker.

“Yeah,” he says. “Me too.”